CO2-Philic Coated Proppant for Fracturing Fluid Viscosity

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Solution Overview

Problem

Conventional CO2-based hydraulic fracturing fluids lack sufficient viscosity to suspend proppant particles, limiting their use due to the lack of CO2-soluble materials for thickening agents, making it difficult to maintain open subterranean fractures during and after fracturing treatments.

Innovation Solution

Viscosifying proppants coated with a CO2-philic coating that dissolves in CO2-based fluids, increasing the fluid's viscosity by at least 25% to effectively suspend proppant particles, thereby enhancing the ability to maintain fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional CO2-based hydraulic fracturing fluids are used, then environmental benefits and non-aqueous properties are achieved, but viscosity is insufficient to suspend proppant particles

Engineering Contradiction:

Improveenvironmental impactVSAvoidviscosity

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

A viscosifying agent is introduced as an intermediary substance that mediates between the CO2-based fluid and proppant particles. The viscosifying agent dissolves in the CO2-based fluid to increase its viscosity, enabling effective proppant suspension while maintaining the environmentally beneficial non-aqueous properties of the base fluid.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The viscosity parameter of the CO2-based fluid is changed by adding a viscosifying agent. This parameter modification transforms the fluid from a low-viscosity state that cannot suspend proppants to a high-viscosity state that provides adequate suspension, while the fluid remains CO2-based for environmental benefits.

Inventive Principle:

Principle #35Parameter changes

2Strength

If thickening agents are added to CO2-based fluids, then viscosity increases, but CO2 is not a good solvent for high molecular-weight polymers

Engineering Contradiction:

ImproveviscosityVSAvoidsolubility

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The molecular weight parameter of the polymer is changed to resolve the solubility issue. By using low molecular weight polymers instead of high molecular weight polymers, the patent achieves both adequate viscosity enhancement and good solubility in CO2, overcoming the limitation of conventional thickening agents.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses low molecular weight polymers that can be easily dissolved and potentially degraded, replacing the need for complex, high molecular weight polymers that are difficult to dissolve and manage in CO2-based systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If proppant particles are added to low-viscosity CO2-based fluids, then fracturing treatment can proceed, but proppant suspension is inadequate

Engineering Contradiction:

Improvefracturing treatment efficiencyVSAvoidproppant suspension stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The viscosifying agent acts as a mediator between the CO2-based fluid and proppant particles. By dissolving in the fluid and increasing its viscosity, it enables the fluid to adequately suspend and transport proppant particles throughout the fracturing process, ensuring both treatment efficiency and proppant distribution stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The use of CO2-philic coated proppants in CO2-based hydraulic fracturing fluids significantly increases viscosity, allowing for effective suspension of proppant particles and maintaining open fractures, reducing the need for additional viscosifiers and improving the efficiency of subterranean treatment processes.

Implementation Method 1

a CO2-philic coating that dissolves in CO2-based fluids, increasing the fluid's viscosity by at least 25%

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

CO2-based fluids are not sufficiently viscous to suspend proppant particles

Methodology Applied

Scientific EffectViscosity:

Data Source

PatentUS10119068B2Viscosifying modified proppant system for carbon dioxide based fracturing fluids

Publication Date: 2018.11.06 SAUDI ARABIAN OIL CO

AI summary

Viscosifying proppants including proppant particles coated with a CO2-philic coating in which the CO2-philic coating has a solvable portion that viscosifies a CO2-based fluid when the viscosifying proppant is added to the CO2-based fluid are provided. Methods of making viscosifying proppants are also provided that include coating proppant particles with a precursor material of a CO2-philic material, and polymerizing the precursor material to form a viscosifying proppant. Viscous hydraulic fracturing fluids include a CO2-based fluid and the viscosifying proppants and methods of treating subterranean formations that include contacting a subterranean formation with a viscous hydraulic fracturing fluid and propagating at least one subterranean fracture are also provided.